Unwind and rewind web tension control



Oct. 30, 1962 w. F. HUCK I UNWIND AND REWIND WEB TENSION CONTROL Filed A ril 10, 1959 5 Sheets-Sheet 1 INVENTOR W. F. HucK 1962 w. F. HUCK 3,061,225

UNWIND AND REWIND WEB TENSION CONTROL Filed April 10, 1959 5 Sheets-Sheet 2 \WWW INVENTOR: W. F. HUCK one ATTOR EY Oct. 30, 1962 w. F. HUCK 3,061,225

uuwmn AND REWIND WEB TENSION CONTROL Filed April 10, 1959 5 Sheets-Sheet 3 1115/ /a. 6/ ms- @l I 2 Oct. 30, 1962 w. F. HUCK 3,

UNWIND AND REWIND WEB TENSION CONTROL Filed April 10, 1959 5 Sheets-Sheet 4 IN VENTOR;

W. F. HUCIQ BY WW ATTORNEY Oct. 30, 1962 w. F. HUCK 3,061,225

UNWIND AND REWIND WEB TENSION CONTROL Filed April 10, 1959 5 Sheets-Sheet 5 INVENTOR: vy. F. Huc K.

I H h F" .6 BY wme in? E:

This invention pertains to means for unwinding or rewinding of web fed materials, such as paper, cloth, felt, tfilm, and the like, and more particularly to means which assure the tight unwinding or rewinding of webs from or to the material roll.

The supply or storage of web fed materials for processing is accomplished by means of wound rolls. In the past, the tension of the unwinding or rewinding web material from or onto the roll has been controlled by constant speed moving belts having, respectively, a less or a greater speed than that of the material. Therefore, these roll drive belts which rotate the roll by frictional contact, actually slip over the roll surface, the web tension being maintained by controlling the contact pressure and varying it to suit requirements. This invention applies to belt type tension control in which the belt contact pressure is constant and suflicient to firmly drive the material r-oll without slippage, and the velocity of the belt is varied to maintain the desired web tension.

In these cases wherein rolls of supply materials are wound or unwound, telescoping of the adjacent material layers comprising these rolls may occur. This condition is usually prevalent in those processes requiring webs, such as paper or the like, having smooth surfaces. The efiect is that a wound concentric portion of such a roll starts to move axially with respect to other portions, causing the sides of such rolls to become so uneven that the roll is unusable.

The cause of this condition is uneven surface-to-surface tension between adjacent concentric layers of wound material so that creep is introduced as the weight of the material, or the frictional force acting against the roll, varies progressively as the roll size changes. This uneven tension may be a result of changes in web temperature, electrostatic fields, drying variations, or other causes, which can deteriorate an originally uniform winding or unwinding condition. Where winding and unwinding frictional force is applied to the outside of the roll, the susceptibility to the creep phenomenon is greatest. In addition, at the end of the unwinding process or at the beginning of the rewind process, there is a tendency for the web material to slip around the core of the roll and this eflect is especially pronounced if anti-friction bearings support the roll core spindle. This invention eliminates this slipping tendency by applying an additional torque directly to the roll core spindle, ensuring tight unwinding and rewinding of the web about the roll core.

The main purpose of this invention, therefore, is to provide means that will constantly correct the defective conditions described above as they occur, by supplying a supplementary torque to the roll core that is opposite, relatively speaking, to that applied to the outside of the roll. This torque is sufiiciently high to tighten the entire roll around the core, but low enough to allow full tension control of the unwinding or rewinding web by belts contacting the outside roll surface. It should be understood that this method will be most effective with drive belts that provide nonslipping contact against the paper roll. Hence, the application of this counter-torque directly to the roll core spindle causes a constant tightening effect during unwinding and rewinding of the web, thereby assuring a closely wound web in the vicinity of the roll core and effectively eliminating telescoping of adjacent web layers.

3,%i,225 Patented Oct. 30, 19fi2 Another purpose of this invention is to provide a friction belt drive to the material roll which will drive this roll positively and uniformly (without slippage) regardless of the size of the roll.

Still another purpose of this invention is to provide means, driven from the rollstand drive, which controls the tension of the unwinding and/ or the rewinding web and maintains this tension constant regardless of the size of the roll.

A still further purpose of this invention is to provide means controlled by the drive belt position to vary the effect of this supplementary torque in response to the varying diameter of the roll.

The preferred form of this invention, together with several variations, is described in the following specification, taken in connection with the appended drawings, in which:

FIGURE 1 is a side elevational View of a device in which the tension is accurately controlled in both un winding and rewinding webs.

FiGURE 2 is a developed plan view of the device shown in FIG. 1.

FIGURE 3 is a partial side elevational view of one alternate form of the device shown in FIGURE 1.

FIGURE 4 is a partial plan view of the device shown in FIG. 3.

FIGURE 5 is a partial side elevational view of another alternate form of this device, specifically suited to control the tension in unwinding webs.

FlGURE 6 is a partial side elevational view of still another alternate form of this device, also specifically suited to control the tension in unwinding webs.

FIGURE 7 is a partial plan view of the device shown in FIG. 6.

FIGURE 1 shows a travelling web of material 11 rewinding on material roll 11a which is supported by cantilevered extensions 12a from frames 12 forming the structural support for a device for rewinding processed material webs onto rolls. During this rewind process the Web enters the rewinding unit by passing successively over rollers 13, 14, 15, and 16. Floating roller 15 located at the end of arms 17 pivots with shaft 18. Also mounted to shaft 18 is arm 19 which carries pulley 26 which, in turn, bears against V-belt 21.

This web rewinding device is driven from the main processing machine drive via horizontal shaft 31, bevel gears 32 and 32a, and cross shaft 33 which has a variable diameter pulley 34 mounted on its shaft extension opposite bevel gear 32a. This variable diameter pulley 34 is preferably of the type disclosed in W. 'F. Hucks United States Letters Patent No. 2,812,666, granted November 12, 1957. V-belt 21 connects pulley 34 to fixed diameter pulley 35 mounted on the extension of belt drive shaft 36.

The rewinding material roll 11:; is frictionally driven by moving belt 41 which passes around pulley 42 on drive shaft 36 and also'passes over stationary idler pulley 43 and movable idler pulley 44. Belt 41 is forced against material roll 11a by the action of fluid pressure against piston 45 in cylinder 46. This action forces lever arms 47, attached to piston rod 48 and carrying idler pulley 44, to rotate about pivot 49, thereby providing a continual equalized frictional contact force between belt 41 and material roll 11a regardless of the diameter of the roll. The magnitude of this contact force may be controlled by pressure regulator 46a in fluid pressure line 46b. Gauge 46c provides means to indicate the magnitude of the fluid pressure within cylinder 46. 1

Material roll 11a is mounted to rotating spindle 51 by means of the construction shown in FIGURE 2. Cone threads 53, act as mounting for spindle core tube 54 about which web 11 tightly wraps. The flanges of cone pieces 52 contain set screws 55 for securely fastening said cone pieces to spindle 51. These flanges also contain radial blind holes 56 into which an adjusting rod 57 can be fitted. This rod provides a convenient means for turning cone pieces 52 on threads 53. Spindle 51 is removable from the machine by means of pivoting handles 53 (carrying bearing blocks 59 having split anti-friction bearings 60) about pin 61 as shown best in FIGURE 1.

The tension in rewinding web 11 is controlled in the manner first disclosed in W. F. Hucks U.S. Letters Patent No. 2,670,907, issued March 2, 1954. This device crnpensates for web tension variations by instantaneous action of the variable speed drive. For example, if the tension in web 11 increases, floating roller 15 tends to move clockwise about shaft 18, thereby forcing rotating pulley against V -belt 21 which travels between fixed diameter pulley and variable diameter pulley 34. This movement of pulley 2% reduces the effective length of V-belt 21, thereby reducing the operating diameter of variable pulley 34, the linear speed of belt 41, and the rotational speed of drive shaft 36. In this manner, the speed of pulley 42 attached to shaft 36 is reduced, thereby reducing the speed of belt 41 contacting roll 11a. Hence, web 11 is rewound onto roll 1111 at a reduced speed and the desired tension condition in web 11 is restored.

Similarly, if the tension in web 11 decreases, floating roller 15 moves downward, thereby moving pulley 20 away from V-belt 21, and increasing the speeds of pulley 34, shaft 36, and roll drive belt 41. Hence, the speed of the rewinding web is increased, thereby increasing the tension in the web to its desired value.

Spindle 51, on which material roll 11a is mounted, has a pulley 72 mounted on its shaft extension. Belt 73 connects pulley 72 to pulley 74 on the extension of drive shaft 36. Belt '73 also contacts idler pulleys 75, 76, and 77, and also take-up pulley 78 which is mounted on arm 36 pivoting about the center of rod 7).

Since the diameter of pulley 74 is larger than the diameter of web drive belt pulley 42, belt 73 and consequently spindle 51 will have a tendency to revolve at a greater speed than material roll 11a (which is frictionally driven by belt 41 from pulley 42), thereby resulting in an additional torque application to spindle 51. This additional torque acting on spindle 51 causes that portion of the rewinding web closest to spindle core tube 54 to wind tightly around said tube.

Correspondingly, when this machine is unwinding web 11 from roll 11a (in the direction opposite to the arrowhead on web 11 in FIGURE 1) the diameter of pulley '74 is made smaller than the diameter of web drive belt pulley 42, and spindle '51 will have a tendency to revolve at a slower speed than the material roll 11a, thereby imparting a retarding torque to spindle 51. This retarding torque causes that portion of the unwinding web closest to spindle 51 to unwind tautly at all times.

An additional feature of this invention is the provision for varying the magnitude of this additional torque in response to the changing diameter of the material roll. This feature is desirable because an additional torque of constant magnitude applied to the roll shaft extension is less effective at higher rotational speeds of the material roll (corresponding to the smaller roll diameters). Hence, the generalization can be made that as the material roll diameter decreases (or increases), the supplementary torque effect should increase (or decrease) proportionally.

Means for accomplishing this are disclosed in FIG- URE 1 wherein compression spring 81, operable between washer 82 and flange 3a on rod 83, urges arm 84 (carrying previously described pulleys 76 and 77) upward about pivot 85, thereby increasing the tension in belt 73 and correspondingly reducing the tendency of belt 73 to slip over pulley '72. Rod 83 is fastened to arm 86 securely mounted to pivot shaft 87 which also has a sec- 0nd arm 83 secured thereto. Link 89 connects arm 88 to lever arm 47. Hence, as the diameter of the rewind- 1ng roll 11a increases, lever arms 47 will pivot downward causing pivot shaft 37 to move counterclockwise and increasing the length of spring 81 thereby reducing the tension of belt 73 and correspondingly reducing the magnitude of the supplementary torque applied to pulley 72, and vice versa for the case of the unwinding rollstand.

The tension of belt 73 may be manually adjusted by nut 91 (contacting abutment 92) engaging screw 93 attached to the lower end of tension spring 94 which acts to pull arm downward about rod 79.

FIGURES 3 and 4 disclose an alternate form of unwind and rewind tension control differing from FIG- URES 1 and 2 in that belt 73, which connected pulley 72 on spindle 51 to pulley 74 on the extension of drive shaft 35, has been replaced by V-belt 101 which connects spindle 51 to a reversible, variable speed motor 102. The connection is achieved by passing V-belt 101 over drive pulley 103 mounted on motor shaft 104, an also over slip pulley 105 mounted on the extension of spindle 51. Slip pulley 105 is a pulley having an oversized V-belt groove 106. Since V-belt 101 does not touch the sides of slip pulley 105, any overspeed or underspeed of V-belt 131 with respect to spindle 51 will cause belt 101 to slip along the bottom of groove 106. I-lence, the unwinding or rewinding web will be kept continually tight around spindle core tube 54 at all times.

These effects are achieved by changing drive pulley 103 to suit the required speed of V-belt 101. For example, when web 11 is being rewound onto roll 11a (asshown in FIGURE 3), a drive pulley 103 of such a diameter is chosen that the linear speed of belt 101 is greater than the peripheral speed of slip pulley 105, thereby applying an additional torque to roll core spindle 51 and assuring tight rewinding of web 11 about core tube 54. Similarly, when the device shown in FIGURE 3, is unwinding web 11, a drive pulley 103 is chosen such that the linear speed of belt 101 is less than the peripheral speed of slip pulley 105, thereby applying a retardmg torque to the roll core spindle 51 and assuring the trght unwinding of web 11 by overcoming any tendency of said web to slip about core tube 54.

'SIIICC the rotational speed of spindle 51 varies as the diameter of roll 11a changes, means are provided to vary the rotational speed of motor 102 proportionally. These means consist of the variable rheostat 107 whose moving contact arm 108 is securely fastened to stub shaft 109 pivoting in the extension 12b of machine frame 12. Shaft 109 also carries arm 110 connected to one end of link 111, the other end of which is pin-connected to lever arm 47. Hence, as the lever arms move in response to changes in the diameter of roll 11a, a corresponding pivoting movement is imparted to arm 108 of rheostat 107, thereby varying the input current to motor 102 and altering its speed proportionally to that of roll 11a. This motor speed control is illustrated in a simple manner for clarity of understanding, but other and equivalent forms of motor speed control can equally well be employed. FIGURE 5 shows another alternate method of applymg a retarding torque to spindle 51 when web 11 is unwinding from roll 11a. In this device another slip pulley 121 is rigidly secured to the extension of spindle 51. Brake belt 122 contacts the periphery of pulley 121, thereby supplying the needed retarding torquev Belt 122 is attached at one end to post 123 projecting from the upper end of arm 124. The other end of belt 122 is fastened to pin 125 in clevis 126 which also has a threaded portion 126a. Nut 127 engages the threaded end 126a of this clevis and provides means for manually adjusting the contact force, and hence the retarding force, between belt 122 and pulley 121.

Means are also provided for varying the braking effect in response to the changing diameter of material roll 11a. These means include pivot shaft 128 to which aforementioned arm 124 and also arm 129 are securely fastened. Link 130 connects arm 129 to lever arm 47. Compression spring 131, operable between abutment 132 on frame 12 and washer 133 bearing against nut 127, provides continual tensioning of brake belt 122. As the diameter of the unwinding roll decreases, the upward movement of arm 47 is converted by the linkage previously described to the clockwise rotation of pivot shaft 128 and arm 124, thereby tightening brake belt 122 around slip pulley 121 and increasing the retarding or braking eifect on spindle shaft 51. This tightening of brake belt 122 has a compressive effect on spring 131, which thereby imparts increased tension to belt 122.

A still more sophisticated and preferred device for applying a retarding torque directly to spindle 51 is shown in FIGURES 6 and 7. This device is a fluid pressure operated brake consisting of flange 141 securely fastened to the extension of spindle 51, and stationary, expandable tire brake element 142 directly connected to fluid pressure line 143. Pressure gauge 144 and cam-operated pressure regulator 145 provide means to vary the magnitude of the retarding elTect on spindle 51. In actual use this fluid pressure brake has been of the pneumatic type which is commercially available from any of several well known manufacturers;

Means for varying this fluid pressure braking effect in response to changing roll diameter are also provided in this form of the invention. These means include cam 146 mounted on the extension of pivot 49 for lever arms 47, said cam engaging roller follower 147 on pressure regulator 145. As the diameter of unwinding roll 11a decreases, lever arms 47 move upward about pivot 49 imparting a corresponding rotational displacement to cam 146. This movement of cam 146 depresses follower 147 thereby opening regulator 145 and increasing the fluid pressure into brake element 142, thereby proportionally increasing the braking effect on roll core spindle 51.

It should be understood that the supplementary torque means herein described acts in conjunction with the roll contacting drive belts and variable speed drive to effectively control the unwinding or rewinding web tension. At no time does this supplementary torque exceed the tension control capacity of the variable speed belt drive.

It should also be understood that FIGURES 1 and 2 illustratethe preferred form of this invention for devices capable of both unwinding and rewinding web materials. FIGURES 6 and 7 illustrate the preferred form of this invention when applied solely to devices for unwinding webs.

While the invention has been disclosed herein in connection with a few preferred embodiments so that those skilled in the art can readily practice the invention, it is not intended thereby to limit the scope of the invention, except as may be required by the state of the prior art and the language of the appended claims.

What is claimed is:

1. In a device for unwinding or rewinding a web of material with respect to a cored roll of such material, a roll-surface drive belt mounted so as continuously to engage the outer surface of the material wound on said roll, positive-acting means for variably adjusting the engagement pressure, power means for driving said drive belt to rotate said roll, means for sensing the tension in the web at a point adjacent its point of arrival at or departure from said roll, means controlled by said sensing means for varying the speed of said drive belt to maintain the same in non-slipping tension-controlling relation to the outer surface of said roll, variable torque-control means constantly connected to the core of said roll, and means for controlling the torque inversely as the diameter of the roll.

2. A device in accordance with claim 1, in which said torque-control means includes an element connected for rotation with the core of the material roll, and a slipping drive connected to said element to apply a torque sufficient to maintain a desired degree of tightness in those turns of web material lying closest to the core.

3. A device in accordance with claim 2, including means responsive to the changes in outer diameter of the material roll for varying proportion-ally the torque applied to said element by said slipping drive.

4. A device in accordance with claim 3 in which said roll-surface drive belt is carried upon at least one idler roller, swinging levers mounting said idler roller, means for urging said levers and said idler roller to a position in which said roll-surface drive belt contacts the periphery of said roll with firm non-slipping engagement, and in which the means responsive to changes in outer diameter of said roll includes at least one of said levers.

5. A device in accordance with claim 2, in which said slipping drive includes a pulley connected to said element and a pulley belt slidably engaging said pulley.

6. A device in accordance with claim 2, in which said slipping drive includes a variable-speed motor in frictional driving relation to said element.

7. In a device for unwinding or rewinding a web of material with respect to a roll of such material, a roll-surface drive belt mounted to engage the outer surface of the material Wound on said roll, power means for driving said drive belt to rotate said roll, an element connected for rotation constantly with the core of the material roll, and drive means for applying to said element an auxiliary torque variable inversely with roll outer diameter, to maintain a desired degree of tightness of the turns of material forming said roll.

8. A device in accordance with claim 7, including means 7 10. A device in accordance with claim 7 in which said means for applying said auxiliary torque includes a braking means.

11. A device in accordance with claim 7, in which said positive drive means includes a motor, and means responsive to the diameter of said roll of material for controlling the torque developed by said motor.

References Cited in the file of this patent UNITED STATES PATENTS 2,070,327 Wood Feb. 9, 1937 2,248,014 Roesen July 1, 1941 2,670,907 Huck Mar. 2, 1954 

